The present invention relates to a device for sealing an orifice wherein a ball-type sealing device is urged against the orifice with a specific force. The invention finds use in hydraulic, pneumatic, or mechanical thrust devices or pistons.
In order to establish complete sealing for mechanical devices such as pushrods, pistons, valves, etc., semi-permanent or intermittent but complete contact must be established at the opening of a cylindrical orifice. To achieve such complete sealing, known elements were machined with high accuracy to provide an accurate fit between the elements. However, such known machinery elements were subject to deviation from the desired dimensions and were quite costly to manufacture.
Another solution to provide complete sealing is to seal the orifice with an element having one or more degrees of freedom. This enables the sealing element to match the corresponding part, such as the structure defining the end of the orifice being sealed, so as to assure permanent and tight contact. If the sealing element were crudely placed opposite the orifice to be sealed, it would not necessarily be centered with respect to the orifice unless the sealing part were also able to enjoy at least one degree of freedom relative to the axis of the orifice. However, in the known devices, asymmetry of the applied stresses by the sealing part may cause lack of homogeneity in the sealing of the orifice.